Light Particle Wave Duality

For as long as light has been studied, people have had different theories on what light is. Early thinkers, such as Aristotle for example, thought that what we saw in the world was a result of sending something out of our eye and having it reflected back. From the end of the seventeenth century leading up to today, there have been two conflicting views of light. The question remains is light a wave or a particle? The answer for many current researchers is light has a wave-particle duality.

A particle is characterized by having extremely small size and a definite location in space at every instant of time. It can also have mass and an electrical charge, as well as momentum and kinetic energy, and as time increases, a particle moves along a calculable path. A wave, however, is best described by things such as waves on the surface of water, sound in a gas, liquid or solid, electromagnetic waves, and displacement of a string with longitudinal or latitudinal motion. In each case there is a quantity varying in some sort of sinusoidal shape. This can be seen by the standard wave equation: y = Asin(kx-wt).